The flagship Mandarin Oriental Hotel was nearly completed
Twelve people have been detained in connection with a fire that partly destroyed the unfinished headquarters of China's state broadcaster.
One of those being held is an official from China Central Television (CCTV), Xinhua state news agency confirmed.
CCTV has apologised for setting off powerful illegal firecrackers that are blamed for sparking the Beijing blaze.
A firefighter died after inhaling toxic fumes and several people were injured in the fire late on Monday.
The tragedy has angered some Chinese, for appearing to show how high-profile groups can bypass normal rules.
Officials from CCTV were using the new building - that housed the near-completed Mandarin Oriental hotel and a culture centre - as the backdrop for an illegal pyrotechnics display.
One or more fireworks hit the tower, which was still under construction so the sprinkler system was not switched on. The 33-storey block may now have to be scrapped.
Among those detained over the incident was Xu Wei, 50, who was in charge of construction at CCTV's new site.
The 12 are being held "on suspicion of creating a disturbance with dangerous materials", an official statement said.
Citing police, Xinhua news agency reported separately that three other CCTV employees and eight people the station hired to set off the fireworks were also under detention.
Authorities said previously the blaze was caused by fireworks that CCTV had illegally set off that were far more powerful than the public was allowed to buy.
It also ignored police orders against setting off the fireworks as part of Chinese lunar new year celebrations.